I admit that one of my time-wasting, egocentric computer activities is to check the day’s Amazon rank of my more recent books by means of a tool called Title Z. It gives you graphs of all the titles you choose on one page.
The Amazon rank of any given book seems to pop around pretty randomly and must be sensitive to even one purchase. But the idea behind Title Z is that you can get meaningful information if you take a snapshot every day. I don’t know whether that’s true, but here is the daily sale’s rank of my The Future of Democracy book since August 17, 2007:
Low is good: a score of 1 would mean that the book was Amazon’s current best-seller. Today happens to be the worst score ever. Who knows if that’s meaningful, but there do seem to be trends in the graph (not just noise). For instance, the fall semester of 2008 was a good time for sales; the current summer has been slow.